The primary goals of this project are to evaluate the parameters of movement as measured by kinematic techniques of Very Low Birth weight (VLBW) infants with and without Neonatal White Matter Disorder (NWMD) and healthy full term (FT) infants without NWMD as detected by ultrasound (US) or magnetic resonance (MRI) over the first 18 months of life corrected age (CA); to evaluate the predictive relations of the parameters of movement to later dysfunction and to compare the prognostic effectiveness of imaging and kinematic techniques; as well as, to evaluate the immature brain's ability to recover from NWMD. At the base, we believe we will begin to describe the early natural history of NWMD and the developing brain's ability to compensate for structural damage. The proposed project is a longitudinal prospective study of 40 VLBW infants with documented NWMD at birth and 40 VLBW infants free of such lesions and 20 FT infants free of NWMD. To characterize the location and size of the lesions and their changes over time, including their appearance beyond the neonatal period, high resolution cranial US will be repeated during the neonatal period and at 3 months CA and MRI will be administered at 6 months CA. The spontaneous and elicited movement patterns of the lower and upper limbs of the three groups Of infants will be evaluated at 2, 5, 9 and 18 months CA using kinematic techniques. The clinical and functional status of the infants will be evaluated with the Neonatal Behavioral Assessment Scale (NBAS) twice during the neonatal period; with the Alberta Infant Motor Screen (MMS) at 5 and 9 months CA; with a standard neurological examination at 6 and 18 months carried out by a pediatric neurologist; with the Peabody Developmental Motor Scales- and with the Pediatric Evaluation of Disability Inventory (PEDI) at 18 months CA. Additionally, to make an initial evaluation of the role of experience, three questionnaires that measure the quality of the caretaking environment will be administered. We expect that infants who have NWMD, particularly near the fronto- parietal junction with or without ventriculomegaly or hemorrhage, will manifest early atypical organization of movement which can be detected by kinematic techniques.